Spark-plug.



C. VH. SMITH.

SPARK PLUG. I Y l -LPPLIOATION FILED JULY 1, 1909. BENEWBD APR. 15, 1911. 1,007,806.

r Patend'Nov. 7, i911.

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` ecil LYm'HL. MM/MKM@ Stimmt] gine ground.

UNITED sTATEs PATENT oEEioE.

CECIL SMITH, OF UNITED STATES NAVY.

SPARK-PLUG.

Application led July 1, 1909,7Se1ia1 No. 505,361.

To all whom it may concern:

.Be it known that I, CECIL H. SMITH, a

citizen of the United States, residing temporarily at Brooklyn Navy Yard, New York', U. S. S. onnectz'cut, have invented vcertain new and useful Improvements in.

Spark-Plugs, of which the following is a specification.

This invention relates to spark plugs for.

gas engines, and has forits object to provide a detachable spark terminal for the en- A further important objectiis to provide 'a spark'terminal which is adapted for engagementlwithvarious plugs when the usual engine ground terminal is broken.

In the drawingl forming apart of the specification, Figure 1 1s a side eleva-tion of my improved spark plug. Fig. 2 is a vertical longitudinal section thereof. Fig. 3 is a horizontal section taken on the line 33 of Fig. 2. Fig. 4 is a detail view ofthe insulating core. A

Referring to the drawing 1 indicates the ycasing' or body member which'may be ofany desired cross sectional form, and has its lower end contracted in diameter as shown at 2 and exteriorly screw threaded fo'r engagement in the engine casing. Centrally positioned within this casing is the insulating core 3 which may be formed of mica or other suitable insulating material. This core is enlarged adjacent to its lower end as shown at 4, and is adapted to be seated upon the .shoulder- 2 formed in the casing 1 by the lower contracted portion 2 thereof.

A cap 5 is disposed upon the upper end of the body member 1, and is formed. with a l depending sleeve 6 which extends into the enlargement fi ofthe core, and is adapted to hold the same against any vertical movement therein. To secure the cap 5 and sleeve 6 within the body 1, a pin 7 is extended through an opening 8 formed in theY easing, and is provided with a groove 8 adjacent to its outer end, to receive the upper bifurcated end ofv a leaf spring 9, which is secured to the exterior of the casing 1. This spring normally tends to force the shank of the pin 8 inwardly into a recess 10, formed in the periphery of the sleeve 6. In this manner any' movement whatsoever of the sleeve and core will beabsolutely prevented.

. Specification of Letters Patent.

Patented Nov. 7, 1911.k Renewed April 15, 1911. serial No. 621,305.

A conducting rod 11 extends centrally through the insulating core3, and has a nut 12 threaded upon its upper end. The circuit wire is` adapted to be secured to the rod 11 and held yin engagement therewith between thenut 12 and the upper end ofthe core. The rod 11 is preferably formed of steel and extends entirely through the core. A terminal point member 13 is attached to the lower end of the core 3, and has its .extremity spaced from the end of the rod 11. The point 13 has its upper portion coiled to resiliently clasp the core, and is of suiiicient resiliency to retain the point in position against all liability of accidental displacement. Adjacent the coiled portion, the terdescribed, and the sleeve and cap are placed upon the'same and bear upon the enlarged yportion 4. thereof. The electric circuit wire is now attached to the upper extremity of the conducting rodl l1, and the nut 12 adjusted to securely retain the wire in position.

The lower portion of the core 3 and consequently the sparking point 13 is now placed in 'the lower contracted extension 2'of the hotly member 1, the base of the enlargement 4 bearing .upon the shoulder 2 thereof. Then the `parts are in this position the opening 8 in the casing 1 and the recess 10 in the sleeve 6 will register. It will be obvious of course, that before the sleeve can be positioned within the body member 1, the pin 7 must be drawn outwardly into the opening 8. After the core has been properly placed within the body of the plug, the pin 7 is released, whereupon the spring 9 will force the pin inwardly into lthe recess 10 and securely lock the various parts in .their operative position. By this corstruction, the plug may be disassembled without the necessity of employing a wrench, and new sparking points may be secured to. the insulating core at a tritling cost, thus practically producing an entirely new plug.

From the foregoing it will be seen that I have provided a spark plug which is of eX- tremely simple construction, the various parts being held in their o erative position against any possibility o accidental derangement. In view of the quick adjust-- ment of the various parts it will be seen that but a few minutes would be required t0 replace the old sparking point by a new one.

My improved spark plug may be very inexpensively manufactured, is highly efficient in 0 eration, and extremely durable in use.

hat is claimed is:

In a spark plug, the combination with a body member adapted t0 be secured in a hydro-carbon engine, an insulating core positioned therein having a portion spaced ripherally from the body member, a conucting member engaged through the core and a spark terminal detachably engaged 20 around the core and bearing against the body member, said terminal member comprising a portion of wire of proper material having a helix at one end ada td for circumscribing engagement with t e core, and a terminal extension adapted to extend longitudinally of the plug and having an inwardly turned portion disposed in juxtaposition with the conducting member, said longitudinally extending portion having an outwardly bowed portlon bearing against the body member, for the purpose described. In testimony whereof I aix my signature, in presence of two witnesses.

CECILI H. SMITH. lVitnesses:

I. C. DAVIS, E. C. HILL.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

